Yun Gu*, Xiaorong Tang, Zhenqi Zhao


Department of Stomatology, The First People’s Hospital of Nantong, Nantong, Jiangsu 226000, China


Introduction: To explore the effect of bracketless invisible orthodontics and fixed orthodontics on salivary flora.

Materials and methods: Patients who underwent bracketless invisible orthodontics or fixed orthodontics in the department of stomatology of our hospital from January 2020 to December 2022 were selected. According to different fixed orthodontic appliances, patients were divided into invisible group and fixed group, including 40 cases of invisible appliances and 44 cases of fixed appliances. Oral plaque samples from the two groups were collected, and the microbial diversity and community structure of the plaque samples were analyzed based on 16S rDNA sequence using the Illumina sequencing platform.

Results: After treatment, PD, GI and SBI in the fixed group were not different from those of the invisible group, but PLI of the fixed group was significantly higher than that of the invisible group (P<0.05). After treatment, the levels of IL-1β and TNF-α in the fixed group were significantly higher than those in the invisible group (P<0.05). Chao1 index and ACE index in the fixed group were higher than those in the invisible group (P<0.05). The bacterial diversity of plaque in the fixed group was higher than that in the invisible group (P<0.05), but there was no significant difference of Alpha diversity between the two groups (P>0.05). With the progress of orthodontic treatment, the differences between the two groups were gradually increased. At the 6th month of orthodontic treatment, the Bray-Curtis distance and Weighted Unifrac distance of salivary flora in the two groups showed significant differences (P<0.05). The two groups of dominant bacteria mainly include: actinobacteria, bacteroidetes, proteobacteria and firmicutes. The most dominant bacteria are actinomyces, corynebacterium, rothia, prevotella and so on. The dominant bacteria in each group were basically the same, but the relative abundance was different.

Conclusion: The abundance, diversity and community composition of plaque in invisible and fixed orthodontic treatment were significantly different, and may be involved in the progress of dental caries, periodontal disease, and other orthodontic complications. Therefore, oral hygiene maintenance should be strengthened regardless of the type of orthodontic appliance worn. 


Oral appliance, invisible orthodontics, fixed orthodontics, salivary flora.